# -*- coding: UTF-8 -*-
from typing import List
from leetcode_helper import TestcaseHelper, SolutionBase


class Solution(SolutionBase):
    # 解题的方法，命名和Leetcode的保持一致即可
    def nextPermutation(self, nums: List[int]) -> None:
        """
        Do not return anything, modify nums in-place instead.
        """
        def reverse(nums, i, j):
            while i < j:
                nums[i], nums[j] = nums[j], nums[i]
                i += 1
                j -= 1

        first_index = -1
        n = len(nums)
        for i in range(n-2, -1, -1):
            if nums[i] < nums[i+1]:
                first_index = i
                break

        if first_index == -1:
            reverse(nums, 0, n - 1)
            return

        second_index = -1
        for i in range(n - 1, first_index, -1):
            if nums[i] > nums[first_index]:
                second_index = i
                break
        if second_index != -1:
            nums[first_index], nums[second_index] = nums[second_index], nums[first_index]
            reverse(nums, first_index + 1, n - 1)


if __name__ == '__main__':
    solution = Solution()

    # 按照leetcode的题目说明，将基本的test case填入
    # 每条case的最后一个元素是正确的结果，即期待的结果
    # 使用元组来保存输入的数据，期待的结果
    testcases = [
        ([3, 2, 1], [1, 2, 3]),
        ([1, 2, 3], [1, 3, 2]),
        ([1, 1, 5], [1, 5, 1]),
        ([1], [1])
    ]

    for case_item in testcases:
        # 获取测试用的case和期待的执行结果

        input1 = case_item[0]

        expect = case_item[len(case_item) - 1]

        solution.nextPermutation(input1)

        # 判断执行结果，输出提示信息
        check_result = solution.check_result(expect, input1)
        TestcaseHelper.print_case(check_result, case_item, input1)

